Buffett reiterated his belief in investing in companies with solid underlying businesses.

Warren Buffett's annual letter to Berkshire Hathaway shareholders was released early Saturday morning, and it included a list of the company's 15 biggest stock holdings as of the end of 2017.

Consistent with his overall views on investing in what he perceives to be solid businesses, Buffett noted in the letter that he and his partner Charlie Munger approach stock trades in a similar way. Buffett wrote:

"Charlie and I view the marketable common stocks that Berkshire owns as interests in businesses, not as ticker symbols to be bought or sold based on their 'chart' patterns, the 'target' prices of analysts or the opinions of media pundits. Instead, we simply believe that if the businesses of the investees are successful (as we believe most will be) our investments will be successful as well. Sometimes the payoffs to us will be modest; occasionally the cash register will ring loudly. And sometimes I will make expensive mistakes. Overall - and over time - we should get decent results. In America, equity investors have the wind at their back."

Here are the 15 biggest stock investments held by Berkshire Hathaway in terms of market value at the end of 2017, excluding the company's investment in Kraft-Heinz: